The Skull Base Surgery Program at the University of Arizona offers a multidisciplinary team of surgeons and specialists who collaborate to offer the full range of cutting-edge surgical, radiosurgical and medical treatments for patients with cranial base disorders. We are dedicated to providing the highest level of clinical care while advancing the field through research and education.
Skull Base Conditions
The cranial base is the point where all of the critical blood vessels and nerves enter and exit the skull. It is one of the most delicate and complex areas of the human body. Diseases of this region include tumors and defects from trauma or present since birth. Symptoms of conditions in the skull base are location-specific and will very much depend upon the surrounding structures that are invaded or compressed by a tumor. Thus, pituitary tumors can cause partial blindness and hormonal dysfunction. Acoustic neuromas can produce deafness, facial paralysis and body weakness.
Diagnosing Skull Base Conditions
Diagnosis of a skull base disorder begins with a complete history and full neurological examination. A detailed description of signs and symptoms along with time and duration of onset helps to determine urgency for treatment. Diagnostic tests, including CT scans and MRIs, are required on almost all cases. Additional modalities such as angiography (traditional digital subtraction and CT angiography) might also be required if critical vascular structures are near to the area in question.
We also have access to more advanced MR imaging techniques including functional, perfusion, and quantitative flow studies, if the proper treatment requires this information. In case of cerebrospinal fluid (CSF) leak, injection of dye through a lumbar puncture might also be necessary to locate the site of leakage.
Ultimately, a tissue sample obtained through surgery is the only way to confirm a diagnosis.
Treating Skull Base Tumors
Treatments for skull base tumors, described below, depend on the diagnosis and progression of disease.
Observation
Some benign tumors are best left untreated in older and asymptomatic patients.
Medication
The first-line treatment of certain tumors, such as pituitary prolactinomas, can include medical therapy. These lesions may shrink in response to medication.
Surgery
Surgery is the mainstay of treatment for most skull base disorders. Surgery allows for pathological diagnosis, decompression of critical structures and possibly a cure.
Radiation
Many skull base lesions are sensitive to radiation. Radiation may also be given as treatment after a lesion has been surgically removed. Radiation may be especially useful if the tumors are diffuse and infiltrate the surrounding structures (skull, brain, blood vessels). Broader beams of ionizing radiation cover the tumor and some surrounding areas. The dose is divided over several weeks to minimize damage to nearby critical anatomy and yet provide a lethal dose to the tumor.
Radiosurgery
Radiosurgery uses “pencil-like” beams of ionizing radiation to precisely target a lesion so that surrounding structures receive little radiation. It can serve as stand-alone therapy or in addition to a surgical resection. Treatments are usually given in 1 to 5 doses. Many tumors, especially those that are difficult to access surgically, are well-controlled with these techniques.
Chemotherapy
Certain aggressive and malignant tumors require systemic therapy. Chemotherapy can boost effectiveness of local control and more effectively treats diffuse infiltration and metastatic disease than would a local surgical resection.
Accessing the Skull Base for Surgery
Working with multiple specialties — including neurosurgery, otolaryngology and oculoplastic surgery — we are able to reach virtually all areas of the brain and skull base to treat conditions using advanced skull base exposures. Whenever feasible we employ minimally invasive approaches through the nasal passages. Less accessible tumors can often be treated with stereotactic radiosurgery.
Expanded Endonasal Approaches (EEA) to the Skull Base
In recent years, a new interest has emerged for the development of “minimally invasive” access to this area, and the nasal passages offer a natural corridor to the anterior skull base. We now can treat a variety of tumors and congenital disorders completely through these passages without a skin incision or craniotomy. This includes more common pituitary tumors, skull base meningiomas and even very rare chordomas and chondrosarcomas.
High-definition endoscopes are used to visualize the anatomy and specialized microsurgical instruments are employed. While cerebrospinal fluid (CSF) leaks after these procedures have been an issue in the past, newer techniques, such as the use of the nasal septal flap (NSF) have minimized complications. For more information, visit the UA Department of Surgery Center for Sinonasal and Skull Base Tumors.
Anterior Craniofacial Surgery (Open)
When tumors of the anterior skull base are too large or exceed our ability to completely address them endonasally, we offer the full range of transbasal, transorbital and zygomatic open skull base approaches. These techniques have been refined over the decades to maximize surgical exposure while minimizing brain injury. Often, the orbital bar (eyebrow ridge) can be safely removed and then replaced to lessen the chance that the brain will be excessively retracted and bruised. Transfacial approaches through the mouth or a facial incision might also be required.
Lateral Skull Base Surgery/Neuro-otology
Tumors at the side of the skull base pose a significant challenge. These will often compress critical cranial nerves or even the brain stem, and significant disability can result. We collaborate with our neurotology colleagues in the Division of Otolaryngology, including Dr. Abraham Jacob in these cases.
We can employ a variety of approaches through the back of the skull or even through the temporal bone, just behind the ear. Typical targets include acoustic neuromas, meningiomas and other benign tumors. The neurovascular team will also use these approaches to reach deep aneurysms or arteriovenous malformations (AVM).
Certain approaches will sacrifice hearing on one side but others can often spare auditory function. Electrophysiologic monitoring of the cranial nerves is critical during these procedures.
Skull Base Radiosurgery
Stereotactic radiosurgery employs many fine beams of radiation that converge on a target. The end result is that the tumor receives a high dose of lethal radiation while the surrounding brain and nerves are spared. Radiosurgery can be highly effective in controlling the growth of many tumors and is particularly useful for inaccessible tumors or in cases where surgical removal would cause too much neurological dysfunction. Often, radiosurgery will follow a formal surgical procedure to obtain tissue for diagnosis or to reduce the size of a tumor and make it a better target for the radiation.
Supporting Services
Skull base disorders can impact many body functions in addition to the nervous system. Depending upon the structures involved, we will obtain full preoperative evaluations by Ophthalmology, Endocrinology, Audiology and Neurology. We are also supported by comprehensive interdisciplinary efforts in Neuro-Oncology, Oncology, Radiation-Oncology, Radiology, Physical Therapy and Rehabilitation Services, as well as Advanced Neuroscience Nursing. While we can offer the full range of medical services relating to skull base disorders, we can just as easily coordinate with you local physicians to facilitate a post-surgical treatment plan closer to home.
Our Tools & Technology
- High-Definition Skull Base Endoscopy
- State-of-the-Art Intraoperative Image Guidance
- Cutting-Edge Surgical Microscopy
- Advanced and CT Angiography
- Cutting-Edge Diagnostic Neuro-Imaging
- Functional and Perfusion MRI
- Stereotactic Radiosurgery
What Sets Us Apart
We have access to more advanced MR imaging techniques including functional, perfusion, and quantitative flow studies. We are also able to reach virtually all areas of the brain and skull bases using advanced skull base exposures. Additionally, we now can treat many tumors and congenital disorders completely through the nasal passages without incisions or craniotomy.
Make an Appointment
For the best neurosurgical care in Tucson, Southern Arizona and the Southwest, you can make an appointment by calling us at (520) 694-1001.